Movable barriers of various kinds are known in the art, including but not limited to horizontally and vertically sliding barriers, vertically and horizontally pivoting barriers, single-piece barriers, multi-piece or segmented barriers, partial barriers, complete barriers, rolling shutters, and various combinations and permutations of the above. Such barriers are typically used to control physical and/or visual access to or via an entryway (or exit) such as, for example, a doorway to a building or an entry point for a garage.
In many cases, a motor or other motion-imparting mechanism is utilized to effect selective movement of such a movable barrier. A movable barrier operator will then usually be utilized to permit control of the motion-imparting mechanism. In some cases a user may control the movable barrier operator by assertion of one or more control surfaces that are physically associated with the movable barrier operator. In other cases such control can be effected by the transmission of a wireless remote control signal to the movable barrier operator.
Such movable barrier operators often serve in part to monitor a parameter that corresponds to force as is applied when moving such a movable barrier. On the one hand, it is desirable to supply sufficient force to ensure that the movable barrier will be able to successfully traverse its entire travel path. This can require, in turn, the need to apply a temporary increase in force in order to permit the movable barrier to move through areas that, for a variety of possible reasons, present greater resistance to movement of the movable barrier. On the other hand, a moving movable barrier can potentially come into contact with an obstacle. When an obstacle occasions resistance to movement of the movable barrier, significantly increasing applied force can potentially lead to damaging the movable barrier, the obstacle, or both. Consequently, many movable barriers closely monitor applied force in order to ascertain when a potentially inappropriate level of force is being applied to thereby permit a safe response.
Notwithstanding the above, even in a system that closely monitors applied force, there nevertheless still exists a desire to detect potential problems within the system to thereby provide even further assurances of safe and effective operation of the movable barrier operator.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are typically not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.